The ring is being sold on Goodwill's online auction site, ShopGoodwill.com. It went up with a starting bid of $1,499 and over the course of a bidding war among more than 30 would-be buyers (so far), that price has soared to $9,000. Bidding closes Tuesday morning.

The ring was brought to the donation center in early June, but no one knows who dropped it off. The rest of the jewelry in the bag was worth about $1,500. But Schray suspected the ring was something special.

"I thought it was really pretty and plain," she said. "I checked for markings on the inside and thought 'Hey, this might be worth something'."

Schray sent the ring to Goodwill's D.C. headquarters to have it appraised. The verdict: A 3.07-carat diamond with a light brown hue, which rests in a 14K yellow gold setting.

Although the ring's original owner remains a mystery, precious items have found their way into a Goodwill donation by accident in the past.

In June, the Panama City News Herald reported that a northern Florida man’s girlfriend accidentally donated a $6,000 engagement ring that he had hidden in a pair of pants. Closer to home, a northern Virginia woman donated an old desk to Goodwill and was amazed when employees discovered a cigar box in the desk containing almost $80,000 in bonds.

But whether the ring was intentionally donated or slipped off an unlucky finger, the money that it will generate should be a huge boon for Goodwill. Proceeds from donated merchandise are used to help vulnerable people gain job skills, access family services and find employment.

"Whoever it was that donated the ring, we're just so grateful," Schray said. "The money will really, really help people in our community."